/*
silverPDF is sponsored by Aleyant Systems (http://www.aleyant.com)

silverPDF is based on PdfSharp (http://www.pdfsharp.net) and iTextSharp (http://itextsharp.sourceforge.net)

Developers: Ai_boy (aka Oleksii Okhrymenko)

Permission is hereby granted, free of charge, to any person
obtaining a copy of this software and associated documentation
files (the "Software"), to deal in the Software without
restriction, including without limitation the rights to use,
copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the
Software is furnished to do so, subject to the following
conditions:

The above information and this permission notice shall be
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR SPONSORS
BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
OTHER DEALINGS IN THE SOFTWARE.

*/
#region PDFsharp - A .NET library for processing PDF
//
// Authors:
//   Stefan Lange (mailto:Stefan.Lange@pdfsharp.com)
//
// Copyright (c) 2005-2008 empira Software GmbH, Cologne (Germany)
//
// http://www.pdfsharp.com
// http://sourceforge.net/projects/pdfsharp
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 
// DEALINGS IN THE SOFTWARE.
#endregion

using System;
using System.Diagnostics;
using System.Collections;
using PdfSharp.Pdf.Internal;

namespace PdfSharp.Pdf.AcroForms
{
  /// <summary>
  /// Represents the signature field.
  /// </summary>
  public sealed class PdfSignatureField : PdfAcroField
  {
    /// <summary>
    /// Initializes a new instance of PdfSignatureField.
    /// </summary>
    internal PdfSignatureField(PdfDocument document) : base(document)
    {
    }

    internal PdfSignatureField(PdfDictionary dict) : base(dict)
    {
    }

    /// <summary>
    /// Predefined keys of this dictionary. 
    /// The description comes from PDF 1.4 Reference.
    /// </summary>
    public new class Keys : PdfAcroField.Keys
    {
      /// <summary>
      /// (Optional) The type of PDF object that this dictionary describes; if present,
      /// must be Sig for a signature dictionary.
      /// </summary>
      [KeyInfo(KeyType.Name | KeyType.Optional)]
      public const string Type = "/Type";

      /// <summary>
      /// (Required; inheritable) The name of the signature handler to be used for
      /// authenticating the field�s contents, such as Adobe.PPKLite, Entrust.PPKEF,
      /// CICI.SignIt, or VeriSign.PPKVS.
      /// </summary>
      [KeyInfo(KeyType.Name | KeyType.Required)]
      public const string Filter = "/Filter";

      /// <summary>
      /// (Optional) The name of a specific submethod of the specified handler.
      /// </summary>
      [KeyInfo(KeyType.Name | KeyType.Optional)]
      public const string SubFilter = "/SubFilter";

      /// <summary>
      /// (Required) An array of pairs of integers (starting byte offset, length in bytes)
      /// describing the exact byte range for the digest calculation. Multiple discontiguous
      /// byte ranges may be used to describe a digest that does not include the
      /// signature token itself.
      /// </summary>
      [KeyInfo(KeyType.Array | KeyType.Required)]
      public const string ByteRange = "/ByteRange";

      /// <summary>
      /// (Required) The encrypted signature token.
      /// </summary>
      [KeyInfo(KeyType.String | KeyType.Required)]
      public const string Contents = "/Contents";

      /// <summary>
      /// (Optional) The name of the person or authority signing the document.
      /// </summary>
      [KeyInfo(KeyType.TextString | KeyType.Optional)]
      public const string Name = "/Name";

      /// <summary>
      /// (Optional) The time of signing. Depending on the signature handler, this
      /// may be a normal unverified computer time or a time generated in a verifiable
      /// way from a secure time server.
      /// </summary>
      [KeyInfo(KeyType.Date | KeyType.Optional)]
      public const string M = "/M";

      /// <summary>
      /// (Optional) The CPU host name or physical location of the signing.
      /// </summary>
      [KeyInfo(KeyType.TextString| KeyType.Optional)]
      public const string Location = "/Location";

      /// <summary>
      /// (Optional) The reason for the signing, such as (I agree�).
      /// </summary>
      [KeyInfo(KeyType.TextString| KeyType.Optional)]
      public const string Reason = "/Reason";

      /// <summary>
      /// Gets the KeysMeta for these keys.
      /// </summary>
      internal static DictionaryMeta Meta
      {
        get
        {
          if (Keys.meta == null)
            Keys.meta = CreateMeta(typeof(Keys));
          return Keys.meta;
        }
      }
      static DictionaryMeta meta;
    }

    /// <summary>
    /// Gets the KeysMeta of this dictionary type.
    /// </summary>
    internal override DictionaryMeta Meta
    {
      get {return Keys.Meta;}
    }
  }
}
